[Jakecs]

Ok so I 've had this strange buzz, moan sound for years and I've never been able to figure it out.

it doesn't happen all the time, but I managed to get it on video this time.

Anybody recognize it? Or is my car as unique as I wouldn't want it to be lol.

 

[ChargedDust]

Do you feel any vibration on the valve cover? I've seen where the baffle was touching the cam cap and maybe that vibration is rattling through the baffle like a megaphone....?

 

[Jakecs]

The baffle on the VC? I had it off weeks ago and it was tight to the top. Why would it be touching?

To add some more detail, it goes away as i rev higher and take off down the road. Its is affected by load and revs.

 

[jamierpm]

try removing serpentine belt and try it out, it almost sounds like my car and it's the alternator, also maybe coming from timing belt, a loose t belt at a certain rpm will cause weird noise, you could remove cover for belt and run engine and see if the belt starts to vibrate when the noise is present, and also check the timing belt tensionner

 

[Jakecs]

Problem with that is the alternator, timing belt, and S belt are all brand new and tensions is good. Like I said, its been doing it for years.

 

[ChargedDust]

The baffle on the VC? I had it off weeks ago and it was tight to the top. Why would it be touching?

To add some more detail, it goes away as i rev higher and take off down the road. Its is affected by load and revs.

Beats me, but I've found some with slight indents in the baffle from the cam cap, wasn't leaking or anything, but was apparently touching.

 

[boost geek]

possible bent valve?

 

[92TurboTona]

i would grab a stethoscope and start probing areas of the engine and rev it up and check

stethoscopes are your best friend when diagnosing internal problems and locations

 

[Jakecs]

Alright lol. I haven't ever heard an internal problem sound like this, but I'll start checking and listening around the top end.

 

[mech1nxh]

PCV system is factory, and in pristine condition???.

 

[NAJ]

Problem with that is the alternator, timing belt, and S belt are all brand new and tensions is good. Like I said, its been doing it for years.

When you are dealing with a possible vibration induced noise the accessory drive belts are always the first to be removed to eliminate them as a cause.
Although the components are new the vibration may be caused by a mounting issue.
Once you have eliminated the accessories engine mounting should be checked next.

NEVER ASSUME, always verify and eliminate everything as a cause.

 

[GLHNSLHT2]

damn time for some PT lifters in that thing.

 

[steve james]

Just for kicks did you ever push the clutch in when it does it maybe a throw out bearing?

 

[patrick l]

I think its belts floping like others said-tension not proper,and or mounting points not tight

 

[Jakecs]

When you are dealing with a possible vibration induced noise the accessory drive belts are always the first to be removed to eliminate them as a cause.
Although the components are new the vibration may be caused by a mounting issue.
Once you have eliminated the accessories engine mounting should be checked next.

NEVER ASSUME, always verify and eliminate everything as a cause.

Ok then, I have checked tension on the serpentine belt as well as the timing belt. That all checks out.

The alt. bushings however are pretty worn, but they are in line.

NAJ, the problem is, diagnosing that way is pretty much impossible. The noise comes and goes, it doesn't last that long, only till it warms up. and if I removed the accessories belts, the noise would aleady be gone anyways. Obviously I cant keep them off.

I jiggled and done everything I can in that area, I suspected it before, a while ago.

Engine mounting is next I suppose.

I am also wondering if its still something to do with the timing belt, not tension, but idk.

 

[Jakecs]

damn time for some PT lifters in that thing.

Lol, I know, but its worse on camera.

 

[NAJ]

Intermitents are difficult to work on, You can only diagnose it when the problem is present unless you can simulate the condition.
You say the Alt bushings are worn but aligned,you will have to wait until the noise appears and the remove the accessory belts one at a time to see if the noise stops.

Timing belt tension is easy enough to check.
Remove the upper cover, start the car and see where the belt rides on the cam sproket.
In Center...Good
On Outside...Too Tight
On Inside...Too Loose

Also I had an issue where both covers were warped and not sitting properly and the belt was actually hitting the cover but as your noise is sometimes louder than other times.
I removed the upper cover and the noise was gone.
The lower cover is warped and is resting against the A/C stationary bracket ans the upper was broken where it latches on to the lower.
I was able to locate new covers thru Mopar(last 2 in the country, uppers will be available when they get to Vintage parts) but they are not going on until I need to replace the belt again.

 

[Jakecs]

Intermitents are difficult to work on, You can only diagnose it when the problem is present unless you can simulate the condition.
You say the Alt bushings are worn but aligned,you will have to wait until the noise appears and the remove the accessory belts one at a time to see if the noise stops.

Timing belt tension is easy enough to check.
Remove the upper cover, start the car and see where the belt rides on the cam sproket.
In Center...Good
On Outside...Too Tight
On Inside...Too Loose

Also I had an issue where both covers were warped and not sitting properly and the belt was actually hitting the cover but as your noise is sometimes louder than other times.
I removed the upper cover and the noise was gone.
The lower cover is warped and is resting against the A/C stationary bracket ans the upper was broken where it latches on to the lower.
I was able to locate new covers thru Mopar(last 2 in the country, uppers will be available when they get to Vintage parts) but they are not going on until I need to replace the belt again.

NAJ thanks for psosting about the cover. I need to ask you something. Did the inside of the cover have any wear from the belt hitting?

Mine does not, but the way i see it, from years of rubbing the warped cover, its may not leave distinct marks.

I'll leave the upper cover off adn see what happens.

Timing tensions is good, checked it your way. The tension was also about perfect on the belt i replaced as well.

 

[sparky305]

I believe I hear what you are referring to. It is at a very narrow RPM range. Are you sure it's not a resonate noise from air passing through the air box, throttle body, or exhaust?

 

[sparky305]

If you truly believe it is something else, like a vibration, how about the metal shield on your trans?